A Prospective Randomized Double Blind Study on Efficacy of Dexmedetomidine and Ketamine as Adjuvant to Epidural Ropivacaine in Lower Abdominal and Lower Limb Surgery

Abstract

Background: Various adjuvants including α-2 adrenergic agonist have been used to prolong the action of local anaesthetics in epidural anaesthesia. Now a days dexmedetomidine is most commonly used adjuvant in epidural anaesthesia but still it may produce side effects like hypotension and bradycardia.There is limited study on efficacy of ketamine as adjuvant in epidural anaesthesia. Aim: The aim of the study was to compare the duration of postoperative analgesia and side effects of epidural dexmedetomidine with ropivacaine versus epidural ketamine with ropivacaine in lower abdominal and lower limb surgery. Methods: This prospective randomised study was carried out in 100 patients of 20-60 years of age and of ASA classes I/II. All the patients, posted for lower abdominal and lower limb surgery were divided into two groups of 50 each. Group RD received 15ml ropivacaine(0.75%) with dexmedetomidine(1µgm/kg) and group RK received 15ml ropivacaine with ketamine(0.5mg/kg).Time for first rescue analgesia request, sensory and motor block characteristics and side effects were recorded. p<0.05 was considered statistically significant. Results: Time of first rescue analgesia request was delayed in group RD (360.15±35.23min) than group RK (311.14±32.48min) which was statistically significant. Both onset of sensory and motor block was earlier and duration of sensory and motor block was prolonged in group RD compared to group RK which was statistically significant. Hemodynamic parameters and side effects were comparable in both groups. Conclusion: Dexmedetomidine is a superior additive to ropivacaine compared to ketamine. Dexmedetomidine provides prolonged postoperative analgesia, earlier onset of sensory and motor block with minimal side effects.